PRE-PACKET ARRIVAL CHANNEL CONTENTION

Description

BACKGROUND

1. Technical Field

[0001] The technology of this disclosure pertains generally to wireless networks, and more particularly to channel contention performed for real-time applications (RTA) on the basis of information about packet size and arrival.

2. Background Discussion

[0002] Most of the devices in the market now have access to the internet through Wi-Fi networks. The WiFi networks are growing every day to allow more throughput and possibility to connect more users to each network.

[0003] However in dense environments, or situations in which interference exists, the latency and reliability is not guaranteed. Wi-Fi networks are considered generally a best effort communication. Real time gaming and delay sensitive applications are a fast developing category where delay and reliability of the data traffic is of great value. For these applications to provide a satisfactory user experience and for the system to reliably function, the end-to-end delay should not be noticeable to the end user, and parameters such as worst case latency become very important. This is because a delay spike might ruin application performance and provide unexpected results.

[0004] Current wireless technologies using CSMA/CA focus on high throughput performance of the network, yet lack adequate low latency capability. However, numerous applications, such as real time applications (RTA), require low latency due to a high timeliness requirement on packet delivery; because the RTA data is valid only when it is delivered within a certain period of time.

[0005] Due to a random channel access scenario, STAs currently need to sense and contend for channel access before transmitting each packet, which can be a source of delay. Other sources of delay include power saving mechanisms, queuing delays and transmission delays which add to end-to-end packet transmission delay.

[0006] Accordingly, a need exists for WLAN protocols which provide reduced delays and communication overheads for real time applications. The present disclosure fulfills that need and provides additional benefits over previous technologies.

[0007] US 2016/0218819 A1 relates to communications, and more specifically to bandwidth acquisition in a network.

BRIEF SUMMARY

[0008] The invention is defined by the appended claims.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

[0009] The technology described herein will be more fully understood by reference to the following drawings which are for illustrative purposes only:

FIG. 1 is a data field diagram of a High Efficiency (HE) Single User (SU) PLCP Protocol Data Unit (PPDU) for an IEEE 802.1 1ax WLAN.

FIG. 2 is a data field diagram of a High Efficiency (HE) multi-user (MU) PLCP Protocol Data Unit (PPDU) format used for downlink multi-user transmission for an IEEE 802.11ax WLAN.

FIG. 3 is a data field diagram of a High Efficiency (HE) Trigger-based (TB) PLCP Protocol Data Unit (PPDU) used for uplink multi-user transmission in an IEEE 802.11ax WLAN.

FIG. 4 is a data field diagram of a Trigger frame for an IEEE 802.11ax WLAN.

FIG. 5 is a data field diagram of a common information field as seen in the trigger frame of FIG. 4.

FIG. 6 is a data field diagram of a user information field as seen in the trigger frame of FIG. 4.

FIG. 7 is a data field diagram of a Block ACK (BA) frame for an IEEE 802.11ax WLAN.

FIG. 8 is a frequency use diagram for Downlink (DL) OFDMA MIMO transmissions performed for an IEEE 802.11ax WLAN.

FIG. 9 is a frequency use diagram for Uplink (UL) OFDMA MIMO transmissions performed for an IEEE 802.11ax WLAN.

FIG. 10 is a flow diagram of using CSMA/CA to allow STAs to gain access to the channel for packet transmission and retransmission in an IEEE 802.11 WLAN.

FIG. 11 is a data field diagram of a data frame format for a regular WLAN system.

FIG. 12 is a data field diagram of an Acknowledgement (ACK) frame format for a regular WLAN system.

FIG. 13 is a communication period diagram for retransmission under CSMA/CA where the back-off time is increased due to retransmissions in a regular WLAN system.

FIG. 14 is a communication period diagram of a packet being dropped after the number of retransmission exceeds the retry limit in a regular WLAN system.

FIG. 15 is a communication period diagram of Downlink (DL) Multi-User (MU) transmission using OFDMA in a regular WLAN system.

FIG. 16 is a communication period diagram of Uplink (UL) Multi-User (MU) transmission using OFDMA in a regular WLAN system.

FIG. 17 is a block diagram of station (STA) hardware according to at least one embodiment of the present disclosure.

FIG. 18 is a network topology diagram showing a topological example addressed according to at least one embodiment of the present disclosure.

FIG. 19 is a communication sequence diagram of a station running a real-time application (RTA) according to at least one embodiment of the present disclosure.

FIG. 20 is a communication sequence diagram showing different channel access scenarios addressed according to at least one embodiment of the present disclosure.

FIG. 21 is a block diagram of primitive parameter communication utilized according to at least one embodiment of the present disclosure.

FIG. 22 is a data field diagram of a New Session request having channel access parameters according to at least one embodiment of the present disclosure.

FIG. 23 is a data field diagram of primitive parameters for a response to the New Session request according to at least one embodiment of the present disclosure.

FIG. 24 is a flow diagram of dynamic adjustment of the early contention window period according to at least one embodiment of the present disclosure.

FIG. 25 is a communication sequence diagram exemplifying an exchange between a non-AP its AP according to at least one embodiment of the present disclosure.

FIG. 26A and FIG. 26B is a flow diagram of a station performing a Pre-Packet Arrival Channel Contention (PPACC) procedure according to at least one embodiment of the present disclosure.

FIG. 27 is a channel access diagram depicting handling a channel busy situation at the beginning of the early channel Contention Window (CW) period according to at least one embodiment of the present disclosure.

FIG. 28 is a channel access diagram depicting another example of handling a channel busy situation at the beginning of the early channel Contention Window (CW) period according to at least one embodiment of the present disclosure.

FIG. 29 is a channel access diagram depicting handling another channel busy situation at the beginning of the early channel Contention Window (CW) period according to at least one embodiment of the present disclosure.

FIG. 30 is a channel access diagram depicting handling a situation in which the channel is not busy at the beginning of an early channel Contention Window (CW) period according to at least one embodiment of the present disclosure.

FIG. 31 is a channel access diagram depicting handling another situation in which the channel is not busy at the beginning of an early channel Contention Window (CW) period according to at least one embodiment of the present disclosure.

FIG. 32 is a channel access diagram depicting handling a scenario in which the channel remains busy from before the early channel CW period into the early channel access period according to at least one embodiment of the present disclosure.

FIG. 33 is a channel access diagram depicting handling a scenario in which the channel is busy at the beginning of the early channel CW period according to at least one embodiment of the present disclosure.

FIG. 34 is a data field diagram of a Pre-Packet Arrival Channel Contention (PPACC) request frame according to at least one embodiment of the present disclosure.

FIG. 35 is a data field diagram of a Pre-Packet Arrival Channel Contention (PPACC) response frame according to at least one embodiment of the present disclosure.

FIG. 36 is a data field diagram of an early contention access request frame according to at least one embodiment of the present disclosure.

FIG. 37 is a data field diagram of an early contention access response frame according to at least one embodiment of the present disclosure.

DETAILED DESCRIPTION

1. Previous WLAN Implementations

[0010] Many 802.11 amendments have been proposed to improve the performance of the WLAN, specifically those who focus on 2.4 GHz and 5 GHz bands. Most of the previous amendments focuses on improving the maximum data rate to be received from 2 Mbits / sec originally proposed to possibly up to 9.6 GHz with the 802.11ax amendment.

[0011] Many techniques have been used to increase the data rate in the physical layer through for example increasing the channel bandwidth from 20 MHz to up to 160 MHz, using new modulations and coding schemes and the introduction of MIMO and Multi-user transmission.

[0012] Other MAC layer improvements have been introduced to reduce the overhead of transmission and hence increase the data throughput. This can be done for example by reducing the interframe spacing, aggregate and segment packets, improving the QoS handling in WiFi networks and applying power consumption protocols to alternate between the awake state and the doze state for station to save their power.

1.1. 802.11ax PPDU formats

[0013] IEEE 802.11ax provides a set of WLAN protocols, and specifies the set of media access control (MAC) and physical layer (PHY) protocols for implementing wireless local area network (WLAN) Wi-Fi computer communication in various frequencies. The IEEE802.11ax standards for the physical layer include the Physical Layer Convergence Protocol (PLCP) sublayer and the Physical Medium Dependent (PMD) sublayer and their interaction with the MAC layer. The MAC layer communicates with the PLCP sublayer using instructions through a service access point (SAP).

[0014] When the MAC layer instructs it to do so, the PLCP prepares MAC Protocol Data Units (MPDUs) for transmission and minimizes dependence of the MAC layer on the PMD sublayer by mapping MPDUs into a frame format suitable for transmission by the PMD. The PLCP also delivers incoming frames from the wireless medium to the MAC layer.

[0015] The PLCP appends a PHY-specific preamble and header fields to the MPDU that contain information needed by the Physical layer transmitters and receivers. The composite frame (the MPDU with an additional PLCP preamble and header) is referred to as a PLCP protocol data unit (PPDU). The MPDU is also called the PLCP Service Data Unit (PSDU), and is typically referred to as such when referencing physical layer operations. The frame structure of a PPDU provides for asynchronous transfer of PSDUs between stations. As a result, the receiving station's Physical layer must synchronize its circuitry to each individual incoming frame.

[0016] In the PMD sublayer, under direction of the PLCP, the PMD sublayer provides transmission and reception of physical layer data units between through the wireless medium by interfacing directly with the wireless medium.

[0017] IEEE 802.11ax defines multiple PPDU formats to transmit packets in different scenarios. They are listed as follows.

[0018] FIG. 1 depicts the High Efficiency (HE) Single User (SU) PPDU format used for single user transmission, which contains the following fields: L-STF as a non-HT short training field; L-LTF as a non-HT long training field; L-SIG as a non-HT SIGNAL field; RL-SIG as a repeated non-HT SIGNAL field; HE-SIG-A as an HE SIGNAL A field; HE-STF as an HE short training field; HE-LTFs as HE long training fields; Data as a data field carrying the PSDUs; and PE as a packet extension field. It should be appreciated that many of these fields are shown span a predetermined time period (exemplified in the figure in µs) instead of a specific number of bits.

[0019] FIG. 2 depicts an HE multi-user (MU) PPDU format used for downlink multi-user transmission. Compared with the single user PPDU format as shown in FIG. 1, this adds the HE-SIG-B field into its format. The HE-SIG-B field provides the channel resource allocation information to each user.

[0020] FIG. 3 depicts an HE Trigger-based (TB) PPDU format used for uplink multi-user transmission. The fields in the HE TB PPDU format are identical to those in the HE single user PPDU format, except that the HE-STF field is 8 µs.

[0021] FIG. 4 depicts the content of the trigger frame having the following fields. A Frame Control field indicates the type of the frame. A Duration field contains network allocation vector (NAV) information used for CSMA/CA channel access. An RA field contains the address for the recipient of the frame. A TA field contains the address of the STA that transmits the frame. A Common Information field includes the information for all allocated STAs, while a User Information field .

[0022] FIG. 5 depicts subfields within the Common Information field seen in FIG. 4.

[0023] FIG. 6 depicts subfields within the User Info field seen in FIG. 4.

[0024] FIG. 7 depicts the content of a block ACK frame. A Frame Control field indicates the type of the frame. A Duration field contains NAV information used for CSMA/CA channel access. An RA field contains the address of the recipient of the frame. A TA field contains the address of the STA that transmits the frame. A BA Control field indicates the policy of the block ACK. A BA info field contains the feedback of the transmission.

1.2. WLAN Features Affecting Delay

1.2.1. Channel Access and Delay Tolerance

[0025] Both contention-based and contention free access are allowed in WLAN devices. The contention based access requires the channel to sense the channel and contend every time the channel is busy in order to gain access to the channel. This introduces additional transmission delay but is necessary to provide for collision avoidance. Contention free channel access allows the AP to gain access to the channel without contention. This is allowed in the Hybrid Control Channel Access (HCCA) where channel access coordination is accomplished by using a shorter inter-frame spacing equal to PIFs (PCF inter-frame spacing) compared to the DIFS (distributed inter-frame spacing) used by other STAs. Although contention free access appears to provide a workable solution to avoid contention packet delay, it is not widely deployed and the majority of WiFi devices are performing contention based access.

[0026] Under contention based access, prior to accessing the channel a STA has to sense the channel and find that it is not busy. This channel is considered busy when: (1) the STA detects a preamble of a frame, with the channel being considered busy for the length of the detected frame; (2) the STA detects energy at more than 20 dB of the minimum sensitivity; or (3) the STA detects the channel as being virtually busy by reading the NAV of a detected frame.

[0027] 802.11ax introduced two NAVs to avoid collision that might arise in falsely relying on the NAV timer. One NAV is for the BSS STAs and the other NAV for the non-BSS STAs, which are maintained separately by the STA.

[0028] 802.11ax uses CSMA/CA for channel access with all legacy 802.11 WLAN devices. For an AP to send a trigger frame for Uplink (UL) Multiple-Input-Multiple-Output (MIMO) transmission it still needs to contend for channel access. In order to enable the AP to obtain (win) channel access over any STA in its BSS, the 802.11ax standard introduced a second set of Enhanced Distributed Channel Access (EDCA) for 802.11ax devices only. This standard allows legacy, non 802.11ax, devices to access the channel freely with EDCA and increase the chance of the AP to gain access of the channel in order to schedule Uplink (UL) or Downlink (DL) Orthogonal Frequency-Division Multiple Access (OFDMA) MIMO data transmission.

1.2.2. Power Saving and Delay Tolerance

[0029] Power saving modes can impact latency as well since stations are shutting down their radio to save power. The AP should buffer data for each STA in its BSS and waits for the STA to wake up to receive it. In some cases the AP needs to content for the channel when the STA is known to be awake and send the STA its packets. The STA might also wake up, contend for the channel and contact the AP to check if there are packets for itself. Another option might allow the AP and the STA to schedule times for the AP and the STA to exchange data. All these options increase transmission packet delays and introduce a trade-off between power saving and delay tolerance.

1.2.3. Multi-user Transmission and Reception

[0030] 802.11 WLAN devices allow the use of MIMO antenna for transmission and reception as well as OFDMA channel access. IEEE 802.11ax supports the multi-user transmission in both uplink (UL) and downlink (DL). This allows multi-stream transmission to one or more users through up to 8 streams for example in SU-MIMO DL in 802.11ac or through multi-user transmission to more than one user through MU-MIMO DL transmission as defined in 802.11ac. This allows the AP to assign one or more streams to STAs in its Basic Service Set (BSS).

[0031] With the use of wide bandwidth channels for data transmission, up to 160 MHz, the channel is expected to be interference frequency selective as some frequencies experience different interference levels than others. This affects the expected achievable packet communication rate and degrades channel performance. To solve this problem, 802.11ax introduced OFDMA where adjacent subcarriers are grouped into resource units (RUs). These RUs can be assigned to different receivers to maximize transmission rate. This scheduling can result in maximizing the Signal of Interest Noise Ratio (SINR) for each receiver and hence allows higher Modulation and coding scheme (MCS) and therefore increases the achieved throughput. It will be noted that SINR is defined as the power of a certain signal of interest divided by the sum of the interference power from all other interfering signals and background noise.

[0032] OFDMA allows many users simultaneous use of the same resources by splitting the frequency domain among them. This results in more efficient use of the resources and can reduce latency since more users can be scheduled at the same time. Also by allowing STAs with small amounts of data to occupy narrow RUs provides increased scheduling efficiency and improved distribution of resources among low-data rate applications that require access to the channel, thus helping to reduce channel access time and overhead of frame headers and preambles.

[0033] OFDMA can be more efficient when it combines with MIMO transmission. An RU can be used to send multiple spatial streams to a STA depending on the MIMO capacities of the STAs. Also, one RU can be assigned to more than one STA to share where each can have one or more spatial streams depending on the MIMO capacities of the STAs. Packing more STAs in the same resource helps in reducing latency for the STAs and APs.

[0034] FIG. 8 depicts an example of DL OFDMA MIMO transmission. The AP is sending a PHY preamble to all STAs to specify the frequency / RUs mapping and RUs assignment for STAs.

[0035] FIG. 9 shows an example of UL OFDMA MIMO transmission. The AP is sending a trigger frame to all STAs which contain the frequency, RU mapping and RU assignments for the STAs. The UL MIMO transmission should be synchronized to the reception of that frame where STAs starts transmission after a Short Interframe Space (SIF) after the reception of the Download (DL) trigger frame.

1.2.4. Retransmission

[0036] FIG. 10 depicts using CSMA/CA to allow STAs to gain access to the channel for packet transmission and retransmission in IEEE 802.11 WLAN systems.

[0037] In CSMA/CA systems, before each transmission and retransmission, the STA has to sense the channel and set a back-off time to contend for channel access. The back-off time is decided by a uniform random variable between 0 and the size of the contention window. After the STA waits for the back-off time and senses that the channel is idle, then the STA sends a packet. The retransmission is required if the STA does not receive an ACK before timeout; otherwise the transmission succeeds.

[0038] When the retransmission is required, the STA checks the number of retransmissions of the packet. If the number of retransmissions exceeds the retry limit, then the packet is dropped and no retransmission is scheduled; otherwise the retransmission is scheduled. If the retransmission is scheduled, then another back-off time is needed to again contend for channel access for this retransmission. If the size of the contention window does not reach the upper limit, the STA increases it. The STA sets another back-off time depending on the new size of the contention window, and the STA waits the back-off time for retransmission and so forth.

[0039] FIG. 11 depicts a data frame format in regular WLAN system. A Frame Control field indicates the type of the frame. A Duration field contains NAV information used for CSMA/CA channel access. An RA field contains the address of the recipient of the frame. A TA field contains the address of the STA that transmits the frame. A Sequence control field contains the fragment number and the sequence number of packet.

[0040] FIG. 12 depicts an ACK frame format in regular WLAN system. A Frame Control field indicates the type of the frame. A Duration field contains NAV information used for CSMA/CA channel access. An RA field contains the address of the recipient of the frame.

[0041] FIG. 13 depicts an example of retransmission in CSMA/CA where the back-off time is increased due to retransmission. In the figure G1 represents short interframe spaces (SIFS), G2 represents DCF interframe spaces (DIFS) and G3 represents ACK Timeout. The data packet frame and the ACK frame use the formats shown in FIG. 11 and 12, respectively. After the transmitter transmits the initial transmission of a packet, it does not receive the ACK before timeout. Then, it sets another back-off time, whereby the size of contention window is 'n' slots. After waiting for the back-off time, the transmitter STA retransmits the packet for the first time. However, the retransmission also fails. The transmitter STA needs to retransmit the packet and sets back-off time again to again contend the channel access. This time, the size of the contention window is doubled, which is 2*n slots, due to the retransmission. The expected back-off time is also doubled by the contention window size. The 2nd retransmission succeeds since it receives an ACK before timeout.

[0042] FIG. 14 depicts an example of a packet being dropped after the number of retransmission exceeds the retry limit. In the figure G1 represents short interframe spaces (SIFS), G2 represents DCF interframe spaces (DIFS) and G3 represents ACK Timeout. The data packet frame and the ACK frame uses the formats previously described. As shown in the figure, after the initial transmission of a packet fails, the transmitter STA retransmits that packet multiple times; however, none of the retransmissions succeed. After retransmitting 'n' times, the number of retransmission exceeds the retry limit and the transmitter STA stops retransmitting that packet and that packet is dropped.

[0043] FIG. 15 depicts an example of downlink (DL) multi-user (MU) transmission using OFDMA. The transmitter AP transmits data packets to its receivers 1, 2, 3, and 4. The data packet could use the High Efficiency (HE) MU PLCP protocol data unit (PPDU) format. After finishing the initial transmission, the AP sends a multi-user Block ACK request (MU-BAR) to all the receivers. The receivers then send Block ACK (BA) back to the AP. According to the content in the BAs, the AP decides to retransmit the packets to receiver 1, 3, and 4. The AP contends for the channel and waits the back-off time, with a first retransmission occurring after the AP gains channel access.

[0044] FIG. 16 depicts an example of uplink (UL) multi-user (MU) transmission using OFDMA. The AP first sends a trigger frame to all the transmitters 1, 2, 3, and 4. The transmitters receive the trigger frame and start the initial transmission using the channel resource allocated by the trigger frame. The data packets could use the HE TB PPDU format. The AP receives the data packets from the transmitters and sends a BA frame to report the correctness of the transmission. Here, only the packet from transmitter 2 is received correctly. The retransmission needs to be scheduled for transmitters 1, 3, and 4. The AP contends for the channel and waits the back-off time to gain channel access, and upon channel access the retransmission proceeds the same as the initial transmission.

1.2.5. UL OFDMA Random Access

[0045] 802.11ax introduced the UL OFDMA random access for UL transmission when the AP does not know which STA has data to transmit or when an unassociated STA wants to transmit data. The trigger frame can allocate some RUs for random UL channel access. When the AP assigns specific RUs for uplink random access the STAs use OFDMA back-off procedure to decide whether they will access the random access channel or not. This is done by selecting a back-off random value and comparing it to the number of RUs assigned for random access. If the current back-off random value is less than the number of RUs, the STA randomly accesses one of the RUs assigned for random access. Random access is expected to be efficient for short packet transmission.

1.2.6. PHY Parameters Affecting Delay

1.2.6.1. Bandwidth

[0046] 802.11 allows for channelization or various bandwidths. The channel assigned for one STA transmission or reception can be 20 MHz, 40 MHz, 80 MHz or 160 MHz. Increasing the bandwidth should generally help increase data throughput and logically free the channel for other user transmissions as users complete their transmission more rapidly. Users thus can more easily obtain channel access. However, other effects can arise to create more delay as bandwidth is increased since the received signals will be more noisy. Also this increased bandwidth increases the possibility of interference with any user that is using part of the locked channel. The channel in this case can be interference frequency selective, which can result in error in reception and retransmission. Retransmission of a WLAN packets is a source of significant delay as previously discussed.

1.2.6.2. Modulation

[0047] 802.11ac allows constellations of up to 256 QAM and 802.11ax allows up to 1024-QAM. Although this can increase the data throughput to up to multiple gigabits, the signal can be very sensitive to noise and interference. If the signal to interference ratio (SIR) and signal to noise ratio (SNR) is not sufficiently high, decoding errors can arise which require retransmissions, which introduce a source of delay that worsens the overall delay of the signal.

[0048] In addition, to increase the number of tones, 802.11ax increases the OFDM symbol length to 12.8 µs and allows multiple Guard Intervals (GIs) to select among them (0.8 µs, 1.6 µs, 3.2 µs) depending on channel conditions and results in decreasing overhead and increasing the efficiency of the transmission.

[0049] 802.11ax allows the duplication of data on the subcarrier through the use of the optional Dual Carrier Modulation (DCM) feature which reduces throughput by half due to the double use of resource, yet it increases the reliability of the transmission thus decreasing Packet Error Rate (PER).

1.2.6.3. Frame Length

[0050] New features added to 802.11 require additional information to be pushed to the preamble and the frame header, which in return results in increasing the overhead and reducing the efficiency of resource utilization. In order to reduce the overhead at such high rates, the maximum length of the frame was increased in 802.11ac to 4,692,480 bytes. For short packets the long frame is not suitable because the overhead would be very high. It will be appreciated that "overhead" is generally considered to be the ratio between "container" bits (headers and other non-data) to the number of bits carried in the data itself.

2. Problem Statement

[0051] A WLAN STA running applications (e.g., real time applications) that are delay sensitive usually suffer significantly, and often are subject to unworkable levels of latency as well as overhead issues when communicated over traditional WLAN services. The current wireless protocols defined in the 802.11 standards are designed to provide a best effort type of service. Although the average delay for packet transmission among WLAN devices is usually good, the worst case delay is often not acceptable for applications that are delay sensitive, such as real-time applications in which data must be communicated in a timely manner.

[0052] One of the main sources of delay in packet transmission is due to the delay associated with channel access. WLAN devices need to sense the channel before accessing the channel. If the channel is found busy, the WLAN device needs to contend for channel access. This is performed by using the CSMA/CA protocol that organizes the channel access and avoids collision when there are multiple devices trying to access the channel at the same time. However the operation of delay sensitive applications can suffer significantly from the delay associated with having to utilize channel contention.

3. Contribution of the Present Disclosure

[0053] In this disclosure a delay arrival contention procedure is described. The STA running an application informs the WLAN device MAC layer of the expected time of arrival of the Real-Time Application (RTA) packet. The MAC layer knowing the expected time of arrival of the RTA packet decides to contend for channel access before packet arrival. This helps in reducing the delay of transmitting the packet once it is received from the application and gets the communication path ready for transmission since the channel has been already reserved for packet transmission.

4. STA hardware configuration

[0054] Each station (STA), whether utilized as a regular station (STA) or as an Access Point (AP) station has external I/O to access to applications, CPU and RAM, to run a program that implements communication protocols. The host machine accommodates Modems which transmit/receive data frames with neighboring STAs. The modem is connected to one or more RF modules to generate and receive physical signals. Each RF module includes a frequency converter, array antenna controller, and so forth. Each RF module is connected to multiple antennas which are controlled to perform beamforming for transmission and reception. In this way, the STA can transmit signals using multiple sets of beam patterns.

[0055] FIG. 17 illustrates an example embodiment 10 of STA hardware configuration showing I/O path 12 into hardware block 13, having a computer processor (CPU) 16 and memory (RAM) 18 coupled to a bus 14, which is coupled to I/O path 12 giving the STA external I/O, such as to sensors, actuators and so forth. Instructions from memory 18 are executed on processor 16 to execute a program which implements the communication protocols, which are executed to allow the STA to perform the functions of a "new STA", or one of the STAs already in the network. It should also be appreciated that the programming is configured to operate in different modes (source, intermediate, and destination), depending on what role it is playing in the current communication context.

[0056] The STA may be configured with a single modem and single radio-frequency (RF) circuitry, or it may be configured with multiple modems and multiple RF circuits as depicted by way of example and not limitation in FIG. 17.

[0057] In this example, the host machine is shown configured with a mmW modem 20 coupled to radio-frequency (RF) circuitry 22a, 22b, 22c to a plurality of antennas 24a - 24n, 26a - 26n, 28a - 28n to transmit and receive frames with neighboring STAs. In addition, the host machine is also seen with a sub-6 GHz modem 30 coupled to radio-frequency (RF) circuitry 32 to antenna(s) 34.

[0058] Thus, this host machine is shown configured with two modems (multi-band) and their associated RF circuitry for providing communication on two different bands. By way of example and not limitation the intended directional communication band is implemented with a mmW band modem and its associated RF circuitries for transmitting and receiving data in the mmW band. The other band, generally referred to a discovery band, comprises a sub-6 GHz modem and its associated RF circuitry for transmitting and receiving data in the sub-6 GHz band.

[0059] Although three RF circuits are shown in this example for the mmW band, embodiments of the present disclosure can be configured with modem 20 coupled to any arbitrary number of RF circuits. In general, using a larger number of RF circuits will result in broader coverage of the antenna beam direction. It should be appreciated that the number of RF circuits and number of antennas being utilized is determined by hardware constraints of a specific device. Some of the RF circuitry and antennas may be disabled when the STA determines it is unnecessary to communicate with neighbor STAs. In at least one embodiment, the RF circuitry includes frequency converter, array antenna controller, and so forth, and is connected to multiple antennas which are controlled to perform beamforming for transmission and reception. In this way the STA can transmit signals using multiple sets of beam patterns, each beam pattern direction being considered as an antenna sector.

5. Topology Under Study

[0060] FIG. 18 illustrates an example topology 30 for the sake of the following discussion. The topology depicts multiple BSSs 32, 34, 36. BSS1 32 is considered to have an Access Point (AP) 38a running non-RTA streams, and an STA 38b running RTA streams, and three STAs 38c, 38d and 38e running non-RTA streams. For the sake of simplicity of illustration, it will be noted that aside from the AP itself, none of the other STAs are considered to be APs. Similarly in BSS2 34 there is an AP 42a running RTA streams, three STAs 42b, 42c and 42d running RTA streams, and STAs 42e and 42f running non-RTA streams. In BSS3 36 there is seen an AP 40a running RTA streams and STAs 40b, 40c, 40d, and 40e running non-RTA streams. The BSSs are sharing the same channel where some of the devices are running RTAs and need to guarantee quick channel access to transmit their data.

[0061] FIG. 19 illustrates an example 50 of STAs running real-time applications (RTAs) which are generating a limited amount of data 52 (one or more packets of limited length) every period of time 54. As seen in the figure, RTA packets are arriving to the MAC layer of the STA running RTA at an expected time and are preferably to be transmitted in real time so that the real-time application continues to be responsive in real-time. Once an RTA packet is received, the next time for an RTA packet to arrive is known before hand. Each BSS contains one AP and multiple STAs, each of which can run an RTA session. Each RTA session is expected to have a packet generated with limited length with specific periodicity.

[0062] As was shown in FIG. 18, stations from multiple BSSs could compete to gain channel access for the RTA sessions and other non-RTA sessions. Each BSS is exemplified with some STAs that run RTAs, and since an RTA has a lower tolerance to delay it should more readily have access to the channel once the packet is ready for transmission. An AP can favor its RTA packets and provide them increased (higher) priority than other STAs in its BSS which request the channel by rejecting the RTS from other STAs in its BSS. An AP still needs to be able to compete with other STAs from other BSSs in the surrounding area.

6. Channel Access Delay

[0063] The packet can experience numerous types of delays after it is generated at the application layer of the transmitter, until the time it is delivered to the application layer at the receiver. One of these delays is the channel access delay, which represents the delay associated with gaining channel access when the channel is free and not in use. The following attempts to identify the source of this delay.

[0064] Any STA using a WLAN is required to listen before it talks, while STAs using CSMA/CA sense the channel before accessing it and avoid collision. Any station before accessing the channel should sense the channel, if the channel is free, the STA can access the channel. If the channel is occupied, the STA should wait until the channel is unoccupied toward minimizing the probability of collision with other STAs trying to access the channel. The channel is considered free or busy through detecting energy on the channel or by receiving a packet header. Due to sharing the medium with many STAs where some are trying to access the channel at the same time, collision avoidance mechanisms are used to prevent two channels from accessing the channel at the same time resulting in the collision of both transmitted packet streams.

[0065] FIG. 20 illustrates some example channel access scenarios 70. In a first instance, a packet 74 arrives 76 during the busy portion 73a of channel activity 72. The STA contends for the channel and performs a random back-off (random back-off timer) 73b, and then accesses 75 the channel to send packet 73c if the channel is not busy.

[0066] Moving to the scenario in the middle of the figure, if an RTA packet 80 arrives 82 when the channel is not busy (free), then the STA gains immediate access 77 of the channel and starts transmitting the RTA packet 78 right away.

[0067] Moving to the scenario on the left side of the figure, it should be appreciated that after RTA packet arrival the STA may be unable to access the channel even when the channel is free again. For instance upon packet 84 arrival 88 that the channel activity 85 is seen showing a busy channel 86a upon packet arrival, so the STA waits until the channel is unoccupied and sets its back-off timer 86b, however, during this time some other channel might gain access to the channel before its back-off timer expires. Thus, after the back-off interval the channel is found to be still busy 86c, which can occur multiple times, with additional back-off intervals 86d, and busy periods 86e, before a back-off interval 86f after which the channel access 87 is gained for packet 89 transmission. The time interval from the RTA packet arrival to the channel access time represents channel access delay and is considered one of the largest sources of delay for WLAN packet transmission.

7. Pre-packet Arrival Channel Contention

7.1. RTA Stream Setup

[0068] The MAC layer should be aware of the packets of the RTA that need to be treated differently. The MAC layer is expected to run special processes (e.g., algorithms) to access the channel and give priority to transmit the RTA packets at the exact time they are supposed to be transmitted. The Application layer upon starting a real time application should inform the MAC layer of the initiation of the RTA session. The application layer upon starting a real time application should inform the MAC layer of the RTA session parameters. The parameters that are used for channel access includes: (a) maximum RTA packet length; (b) maximum number of packets to be received for each channel access; (c) RTA packet channel access periodicity; (d) expected time the RTA packet is to be generated and sent to the MAC; and (e) maximum delay tolerance.

[0069] FIG. 21 illustrates an example embodiment 110 in which primitive parameters from the application layer or any other higher layer 112 are sent to the MAC layer 114 above PHY layer 116.

[0070] FIG. 22 illustrates an example embodiment 130 of a New Session request having channel access parameters, including at least the following.

(a) A New Session Request is a field indicating that the Application layer is initiating a new RTA session if set to a first state. If not set to this first state, the following parameter represents an update to the previously initiated RTA session. It should be appreciated with this and other fields described in the document that either positive or negative logic may be utilized for single bit True/False fields, and any desired form of representation for multibit fields without departing from the teachings of the present disclosure. The MAC layer should initiate an RTA session upon receiving a new session request and accepting it. The details of initiating the RTA session are discussed in the following sections.

(b) A Session ID field is utilized by the application layer to indicate a session ID in referring to the initiated RTA session. The MAC layer associates the following parameters to the session ID. Any further communication between the higher layer and MAC layer regarding this RTA session should include this session ID. This includes updating, deleting or modifying the RTA session.

(c) A Maximum RTA Packet Length field represents the maximum size of each packet delivered to the MAC layer in bits or with respect to time. The MAC layer uses this information to estimate the time needed for each channel access for the RTA.

(d) A Number of Packets to be Received field for each channel access refers to the maximum number of packets to be delivered to the MAC layer for each RTA channel access. The MAC layer uses this information to estimate the time needed for each channel access for the RTA. It should be appreciated that the previous two variables can be combined into one variable if the higher layer sends the time required in each channel access instead of the number of packets and packet size.

(e) An RTA Packets Channel Access Periodicity field represents the time the MAC layer should expect the next RTA packets to arrive after one expected time for the RTA packet. This is the periodicity of the channel access for the RTA packets. The MAC layer uses this information to estimate the time where RTA packets will be arriving from the higher layer.

(f) Maximum Delay Tolerance is a field representing the maximum delay tolerated by the packet received from the high layers. The MAC layer might drop the packets and not keep trying to deliver it after the maximum delay tolerance is expired.

(g) Session Life Time is a field representing how long (duration) that the RTA session is active. This can be represented as a time relative to the start of the RTA packet generation time, or can be represented in terms of a number of periodic cycles of RTA packet transmission. The MAC layer is expecting the RTA packet arrival for the period of time defined by the session life time.

[0071] FIG. 23 illustrates an example embodiment 150 of primitive parameters of the response to the New Session request that the MAC layer can send to higher layers in response to the RTA stream initiation and received parameters, which as described below.

(a) A Response field indicates if the requirements received are achieved as is. If set to a first state (e.g., one) then the application layer need not change its parameters. If set to a second state (e.g., zero), the application layer should either accept the suggested parameters or resend a new set of parameters.

(b) Session ID field indicates which RTA session this response and parameter refers to. The application layer uses this information to match the session ID with all other RTA running sessions.

(c) Maximum RTA Packet Length field represents the suggested maximum size of each packet delivered to the MAC layer in bits or time in case the response was zero. The MAC layer uses this information to estimate the time needed for each channel access for the RTA.

(d) Maximum number of packets to be received for each channel access is a field representing the suggested maximum number of packets to be delivered to the MAC layer for each RTA channel access in case the response number of packets is indicates as zero. The MAC layer uses this information to estimate the time needed for each channel access for the RTA. It should be noted that the above two fields can be combined into one variable if the higher layer sends the time required in each channel access instead of the number of packet and packet size.

(e) An RTA Packets Channel Access Periodicity field represents the suggested time the MAC layer can expect the next RTA packets to arrive after one expected time for the RTA packet in case the response field in the message was set to zero. This is the periodicity of the channel access for the RTA packets. The MAC layer uses this information to estimate the time where RTA packets will be arriving from the higher layer.

(f) A Maximum Delay Tolerance field represents the suggested maximum delay tolerated by the packet received from the high layers in case the response field in the message was set to zero. When the response is zero this indicates that the MAC layer is suggesting a new parameter to the APP layer and is not accepting the parameter requested by the APP layer. The MAC layer might drop the packets and not keep trying to deliver it after the maximum delay tolerance is expired.

(g) A Session Life Time field represents how long the RTA session is active, and can be specified in time relative to the start of the RTA packet generation time, or it can be specified in terms of the number of periodic cycles of RTA packet transmission. The MAC layer is expecting the RTA packet arrival for the period of time defined by session life time.

7.2. Contention and Channel Statistics

[0072] To allow the STA to prepare for RTA packet transmission at the appropriate time, the STA needs to collect statistics about how busy the channel is. If the channel is completely free, the STA can access the channel without contention. If the channel is occupied, the STA is configured to wait for the channel to be free and run a back-off timer to access the channel. Once the timer expires the STA can access the channel. To make certain that the RTA packet is delivered on time the channel should be reserved, or about to be reserved, at the time when the packet arrives. The STA needs to know the statistics of the channel to make the right decision about when to try and access the channel.

[0073] Channel statistics can comprise one or more of the following. (a) Number of STAs which are accessing the channel, and this can be further divided into: (a)(i) number of STAs around accessing the channel from the same BSSID where the STA is part of; (a)(ii) number of STAs around accessing the channel and belongs to a different BSSID than the one the STA is part of; and (a)(iii) number of STAs around accessing the channel and it can't be detected which BSSID it is part of. It will be noted that the STA can utilize the detected PHY headers and possibly MAC header to estimate the statistics. (b) Percentage of time the channel is occupied by other STAs, which can be furtherly divided into: (b)(i) percentage of time the channel is occupied by STAs of the same BSSID; (b)(ii) percentage of time the channel is occupied by STAs of different BSSID; and (b)(iii) percentage of time the channel is occupied by STAs where the BSSID is not identified. It should be noted that the STA can utilize the detected PHY headers and possibly MAC header to estimate these statistics. (c) Channel delay access time represents the average time for accessing the channel once a packet is ready to be transmitted. (d) Back-off timer interruption statistics represent the statistics for the number of times the back-off timer is interrupted.

[0074] It will be noted that the STA does not have to be awake at all times to collect these statistics, for example the STA can wake up (periodically or in response to state/inputs) and calculate these statistics every period of time. The STA can also only collect the statistics while it is trying to access the channel which allows the STA to conserve energy and thus it does not need to wake up solely for the purpose of collecting statistics.

7.3. Early Contention Window Period

[0075] Once the STA establishes an RTA session it starts running a timer for the next RTA packet arrival. According to the present disclosure, the STA can contend for channel access even before RTA packet arrival. This is to avoid someone gaining access to the channel immediately prior to packet arrival. If the channel is busy during the period of time before packet arrival by the early contention window period, the STA should start contention. If the channel is free during that time, the STA continues to monitor the status of the channel. The size of the early contention window period should be related to the collected statistics, where the statistics are showing that the channel is more highly occupied (e.g., more STAs, more time the channel is occupied, higher channel access delay or higher back-off timer interruption ratio). The early contention window period length can be manually set to a fixed value or can be dynamically adjusted according to channel statistics.

[0076] FIG. 24 illustrates an example embodiment 170 representing dynamic adjustment of the early contention window period. Once the routine begins 172 an RTA session is initiated 174, and the early Contention Window (ECW) period is set to zero or an initial value 176. Over a period of time the statistics of the channel are updated, depicted in this flow chart as a loop, and the more the channel is congested the more the ECW period is increased in value. Once the channel is less congested, the value of the ECW period decreases.

[0077] In particular, channel statistics are collected 178, then a check made 180 if the channel is more or less occupied. This determination depends on a threshold level, above which the channel is considered "more" occupied, and below which it is considered "less" occupied. If found to be less occupied, then execution reaches block 182 and the ECW period value is decreased toward a minimum value (e.g., zero). Alternatively, if found to be more occupied, then execution reaches block 184 and the ECW period value is increased toward a maximum value. A check is made 186 if the RTA session is still active. If it is still active, then timer expiration is awaited 188 with a return to block 178; otherwise execution ends 189.

[0078] It will be noted that for the sake of simplicity of illustration this and other flow diagrams depict the flow simply in a time-linear manner. However, it will be appreciated that the steps being executed can be performed in a multitasking or multikernel environment, where steps in the flowchart are being performed in its task and/or thread while other actions are being performed for other tasks and/or threads.

7.4. Early Channel Access Window

[0079] The STA running RTA may occupy the channel before the RTA packet estimated arrival time to guarantee that no other stations will occupy the channel at that time. The period of time before the estimated arrival of the RTA packet that the STA is allowed to occupy the channel is the early channel access window (ECAW). During this time if the STA decides to gain access to the channel, the STA starts transmitting packets to the intended STA, or any other STA, on condition that by the estimated RTA packet arrival time the STA will be ready to transmit the RTA packets. If the STA does not have any packet to transmit during the ECAW and it needs to occupy the channel, the STA transmits a null or dummy packet for the sake of occupying the channel and not allowing anyone else to use the channel. ECAW is expected to be a small period of time and should not result in over occupying the channel with unnecessary transmissions.

7.5. RTA Pre-packet Arrival Channel Contention AP Enablement

[0080] An AP can commence early contention for the channel at any time once it has an active RTA session. A non-AP STA should acquire approval by the AP prior to performing early contention for the RTA packets. For example, a non-AP STA sends a request of pre-packet arrival channel contention to the AP of the BSS that it is part of. In at least one embodiment, the request contains the parameters that the non-AP is requesting to use (Early Contention Window (ECW), or Early Contention Access Window (ECAW) ). The AP can accept the non-AP use of early contention or reject it. In rejecting the non-AP use of the requested parameter, the AP can a suggest new set of parameters. In this case the non-AP STA should re-request the enablement of the pre-packet arrival channel contention with the new suggested parameters. At any point of time while the RTA session is active, the non-AP STA is able to send a request to update the ECW and the ECAW parameters. The AP should accept the pre-contention parameter requested by the non-AP STA.

[0081] FIG. 25 illustrates an example embodiment 190 of a communication exchange between a non-AP 192 STA and its AP 194. A non-AP STA sends a Pre-Packet Arrival Channel Access (PPACC) Request 196 to the AP it is associated to. The AP responds to this request with PPACC Response 198, which includes a rejection or acceptance to the request. If the request is rejected it can include new suggested PPACC parameters. In this case the non-AP can repeat the request to the AP with the new suggested parameters.

[0082] When the request is approved, the non-AP STA can update the periods for the early contention at any time by sending early contention access request 200. The AP can approve or reject the period change request through the early contention access response 202. Multiple early contention access request and response exchanges 204, 206 can be performed.

8. Pre-packet Arrival Channel Contention Procedure

[0083] FIG. 26A and FIG. 26B illustrate an example embodiment 210, 230 of a STA performing the PPACC procedure once it gets a request from the higher layers to start an RTA session. The procedure starts 212 and a STA receiving RTA request from higher layers first establishes 214 the RTA stream and performs the steps necessary to get it ready for transmission. A check is made 216, if the STA is an AP STA. If it is not an AP station, then in block 218 it sends a request to the AP first to enable the PPACC procedure, before reaching block 220. Otherwise, if the STA is an AP it can start using the procedure directly, and reaches block 220. The STA sets up a count down 222 to the next RTA packet transmission. It uses the information from the high layer about the estimated time to receive the RTA packet from the higher layer and adds to it any additional delays for buffering or preparing the packet. The STA keeps monitoring 222, 224 the count-down timer (counter / timer) until the value of the count-down timer reaches the early contention window period, at which time execution reaches block 232 of FIG. 26B since the count-down timer has reached the early contention window period, so the STA checks for the status of the channel. If the channel is not busy the STA will keep monitoring it by updating 242 packet countdown, and checking 244 for the counter being less than the early channel access period. If the counter is less than the early channel access period, then a return is made to block 232 with another check for channel busy, otherwise execution reaches block 246.

[0084] If block 232 detects at any time the channel is busy the STA starts 234 a contention procedure, to give higher priority for the STA to access the channel immediately after the channel becomes free again. The packet countdown value is updated 236, and if it is found at check 238 that the counter is less than the early channel access period, then execution returns to block 232. Otherwise, execution reaches block 240 checking if the counter is still greater than zero. If the counter is not greater than zero then block 252, which is described below, is reached. Otherwise if the counter has not reached zero as determined at block 240, then at block 246 the STA reserves the channel by transmitting null or dummy packets until the RTA packet is ready, and then updates 248 the packet countdown, checks 250 for the counter reaching zero, and loops with block 248 until the counter has reached zero, at which time block 252 is reached which transmits the RTA packet and the process ends 254.

[0085] Thus, it has been shown that if the STA gained access to the channel before the early channel access period, the STA keeps monitoring the channel and does not start accessing the channel. If the STA gained access to the channel after the early channel access period, then the STA starts accessing the channel to transmit the RTA packet if it is ready to send dummy packets or padding (null packets) to reserve the channel until the RTA packet is available. If the channel remained in a not busy (free) state until the early channel access period, then the STA should access the channel to transmit dummy packets or padding for reserving the channel until the RTA packet is available.

9. Pre-packet Arrival Channel Contention Examples

[0086] In this section are presented numerous example scenarios for Pre-Packet Arrival Channel Contention (PPCAA) and how each are addressed by the disclosed procedure.

[0087] FIG. 27 illustrates an example embodiment 270 of handling a channel busy situation at the beginning of the early channel Contention Window (CW) period, showing operations during channel busy 282, back-off period 284, null packet sending 286 and RTA packet sending 288 for this situation. Pre-packet arrival channel sensing is performed 272 and the channel monitored 274. The STA starts a contention access process during the busy period to gain access to the channel. The STA gains access 277 to the channel during an early channel access period 278, which extends to the time of RTA packet arrival 280. Early channel access period 278 is the latter part of the early CW period 276, which extends from the time of pre-packet arrival to the time of RTA packet arrival 280. The STA reserves the channel by sending nulls 286 to itself until the RTA packet 288 is ready for transmission. The STA can thus transmit a null or other extraneous placeholding packet often referred to as 'dummy packet', to reserve the channel so that other STAs are unable to access the channel until the RTA is ready. It will be appreciated that for the sake of the simplicity of illustration, the term null packet will be utilized herein, but should be understood to mean the use of any desired forms of placeholder (dummy) packets.

[0088] FIG. 28 illustrates an example embodiment 290 of handling channel busy condition at the beginning of the early channel CW period, showing operations in relation to channel busy 292, back-off 294, non-busy periods 296, and the sending of null packets (or similar) 298, across an early CW period 304 as well as RTA packet 300. Pre-packet arrival sensing 302 commences, with the channel being monitored 303, and the STA begins contention and gains access to the channel, starting a back-off interval 294 at the early CW period and before the early channel access period 306. The STA, however, does not reserve the channel and thus keeps monitoring the channel, which becomes available 296 (non-busy). As the early channel access period 306 begins, the STA reserves the channel to itself until RTA packet arrival 308, such as by transmitting a null or dummy packet to reserve the channel so that no other STAs can access the channel until the RTA packet is arrives 308, and is this RTA packet 300 is transmitted.

[0089] FIG. 29 illustrates an example embodiment 310 of handling a channel busy situation at the beginning of the early channel CW period 322, showing busy 312a, 312b, back-off intervals 314a, 314b, sending null packets 316 and STA packets 318. Pre-packet arrival sensing 320 commences, with the channel being monitored 321, during a busy period 312a with the STA starting contention and gains channel access of the channel with back-off period 314a prior to the early channel access period. The channel becomes inactive 313, then is busy 312b and the STA gains access to the channel and starts a back-off period 314b during which the early CW period begins. In the early channel access period 324, the STA begins transmitting null or dummy packets 316 to reserve the channel so that no other STA can access the channel until RTA packet arrival 326 and transmission 318.

[0090] It will be seen above that the STA does not reserve the channel and continues monitoring the channel until the early channel access period. If the channel gets busy again, the STA starts contention again and once it gains access to the channel it reserves the channel to itself until the RTA packet is ready to be transmitted.

[0091] FIG. 30 illustrates an example embodiment 330 of handling the scenario in which the channel is not busy at the beginning of an early channel Contention Window (CW) period. The figure depicts channel busy 332, back-off interval 334, sending null packet(s) 336 and STA packet 338. Pre-packet arrival channel sensing 340 commences during the early CW period 342 with the STA monitoring 341 channel status. In this example, the channel became busy during the early CW period but before the early channel access period 344. The STA starts contending to gain access of the channel, and upon gaining channel access it commences a back-off period 334 which extends into the early channel access period 344. The STA reserves the channel to itself until the RTA packet is ready to be transmitted, such as by transmitting a null or dummy packet 336 to reserve the channel so that other STAs cannot access the channel until RTA packet arrival 346 and the RTA packet 338 is transmitted.

[0092] FIG. 31 illustrates an example embodiment 350 of a scenario in which the channel is not busy at the beginning of the early channel CW period. The figure depicts sending null packet(s) 352 and STA packets 354. Pre-packet arrival channel sensing 356 is seen occurring when the channel is not busy in the early CW period 358. The channel remains available (not busy) during the early CW period and before the early channel access period 360. The STA reserves the channel to itself at the start of the early channel access period 360, such as by transmitting a null or dummy packet 352 to reserve the channel, so that no other STA can access the channel until RTA packet arrival 362 and sending of RTA packet 354.

[0093] FIG. 32 illustrates an example embodiment 370 of a scenario in which the channel remains busy from before the early channel CW period 380 and into the early channel access period 382. The figure depicts channel busy 372, back-off interval 374, and transmitting STA packets 376. From the time of pre-packet arrival channel sensing 378 and during early CW period 380 the STA monitors 379 the channel status. The STA starts contending to gain access of the channel. The channel remains available (free) before RTA packet arrival 384 and the STA starts the back-off timer 374. The STA gains access to the channel after estimated RTA packet arrival time 384 is reached, and then it is seen transmitting the RTA packet 376.

[0094] FIG. 33 illustrates an example embodiment 390 of a scenario in which the channel is busy at the beginning of the early channel CW period. The figure depicts channel busy 392, back-off interval 394, and transmitting STA packets 396. From the pre-packet arrival channel sensing 398 and during early CW period 402 the STA monitors 400 channel status. The STA starts contending to gain channel access during the early channel access period 404, and the channel becomes free after the RTA packet arrival time 406 and the STA starts a back-off period 394. The STA gains access to the channel after the estimated RTA packet arrival time 406, and transmits the RTA packet 396 after the back-off period 394.

10. Frame Format

10.1. PPACC Request

[0095] FIG. 34 illustrates an example embodiment 410 of a Pre-Packet Arrival Channel Contention (PPACC) frame which is sent by a non-AP STA to the AP STA it is associated to in its BSS to request using the Pre-Packet Arrival Channel Access procedure. The non-AP STA is expecting a response from the AP STA to accept or reject the request. The fields of this PPACC frame are as follows. (a) A Frame Control field contains all the necessary information to identify the frame. (b) A PPACC Request field is set to a first state (e.g., 1) to indicate that the non-AP STA is requesting a PPACC procedure enablement. The AP STA compares request field to the network setting and approves or rejects this request. (c) An ECW Length field indicates the requested ECW period length (time for example) to be used by the non-AP during the PPACC procedure. The AP STA compares this to the network setting and approves or rejects this value. (d) An ECAW Length field indicates the requested ECAW period length (time for example) to be utilized by the non-AP during the PPACC procedure. The AP STA should compare this to the network setting and approve or reject this value. (e) A PPACC length field indicates the period the PPACC is requested to be active in the non-AP STA. If this request is approved the STA will be running the PPACC for this period length (time or number of beacon intervals). A value of zero indicates unlimited time periods.

10.2. PPACC Response

[0096] FIG. 35 illustrates an example embodiment 420 of a PPACC response frame which is sent by an AP STA to the non-AP STA in its BSS in response to a request to use the Pre-Packet Arrival Channel Access procedure. The non-AP STA is expecting the response from the AP STA to accept or reject the request. The fields of the PPACC response frame are as follows. (a) A Frame Control field contains all the necessary information to identify the frame. (b) A PPACC Response field is set to a first state (e.g., 1) to indicate that the non-AP STA is accepting the PPACC request for the PPACC procedure enablement otherwise it is rejected. The STA receiving this response will enable the PPACC procedure if the response is such that the request is accepted. If the response indicates a rejection, then the non-AP STA can resend this request with other parameters. (c) A Suggested ECW Length field only exists if the PPACC Response is set to 0. This indicates the suggested ECW period length to be used by the non-AP during the PPACC procedure in case the request is rejected, but the AP is still willing to enable the PPACC procedure for the non-AP STA under the suggested conditions. The AP sets this field to 0 if it is not willing to enable the PPACC procedure for the non-AP STA. (d) A Suggested ECAW Length field only exists if the PPACC Response is set to 0, which indicates the suggested ECAW period length to be used by the non-AP during the PPACC procedure in case the request is rejected, yet the AP is still willing to enable the PPACC procedure for the non-AP STA. The AP sets this field to 0 if it is not willing to enable the PPACC procedure for the non-AP STA. (e) A Suggested PPACC length field only exists if the PPACC Response is set to 0. This indicates the suggested PPACC length to be used by the non-AP during the PPACC procedure in case the request is rejected and the AP is still willing to enable the PPACC procedure for the non-AP STA. The AP sets this field to 0 if it is not willing to enable the PPACC procedure for the non-AP STA.

10.3. Early Contention Access Request

[0097] FIG. 36 illustrates an example embodiment 430 of an early contention access request frame as sent by a non-AP STA to the AP STA that it is associated to in its BSS to request updating the parameters of the Pre-Packet Arrival Channel Access procedure. The non-AP STA is expecting a response from the AP STA to accept or reject the request. The fields are as follows. (a) A Frame Control field contains all the necessary information to identify the frame. (b) An ECW Length field indicates the requested updated ECW period length (time for example) to be used by the non-AP during the PPACC procedure. The AP STA can compare this to the network setting and approve or reject this value. (c) An ECAW Length field indicates the requested ECAW period length (time for example) to be used by the non-AP during the PPACC procedure. The AP STA should compare this to the network setting and approve or reject this value.

10.4. Early Contention Access Response

[0098] FIG. 37 illustrates an example embodiment 440 of an Early Contention Access response frame which is sent by an AP STA to the non-AP STA in its BSS in response to a request to update the parameters of the Pre-Packet Arrival Channel Access procedure. The non-AP STA is expecting the response from the AP STA to accept or reject the request. The fields of the Early Contention Access Response frame as follows. (a) A Frame Control field contains all the necessary information to identify the frame. (b) An Early Contention Access Response field is set to a first state (e.g., 1) to indicate that the non-AP STA is accepting the Early Contention Access request for the PPACC procedure enablement otherwise it is rejected. The STA receiving this response will update the Early Contention Access parameters of the PPACC procedure if the response is such that the request is accepted.

11. Summary

[0099] Each STA keeps track of the active RTA session and identifies the running RTA session by: (a) rate of packet arrival; (b) size of packet to be sent; (c) expected time of packet arrival; and (d) end of the RTA session.

[0100] The STA is aware of the time the packet arrives to the MAC queue and attempts to gain access to the channel before packet arrival from information provided by the application layer to the MAC layer of the WLAN device.

[0101] In order to maintain fairness in its resource sharing, in at least one embodiment pre-packet arrival channel access is only allowed if the amount of data to be sent is limited, such as less that a specific amount or only a limited period of time or limited Transmit Opportunity (TXOP) (e.g., less than specific amount). It will be noted that TXOP is the amount of time a station can send frames when it has won contention for the wireless medium.

[0102] The STA keeps track of (monitors) statistics that quantify the expected pre-packet channel contention. Every time the STA accedes (releases or relinquishes) the channel and its pre-packet statistics are updated.

[0103] A STA request from the AP to run the RTA pre-packet contention procedure through exchanging messages or communicating request and response with the AP. Once accepted, the STA can request to change the procedure parameter through exchanging parameter update messages with the AP. The STA runs a count down timer from the last packet arrival time to estimate the next arrival time for the new packet. The STA shall start contending for the channel before the counter expires by a time offset related to the collected statistics of the channel contention time or manually defined if the channel was busy at any time after the timer reaches the threshold. In at least one embodiment, this time offset is bounded by a specific amount (e.g., for example 1 TXOP) and should not exceed that amount. If the channel is not busy the STA continues monitoring the channel.

[0104] The STA shall gain access to the channel if it is not busy before the counter expires by a time offset related to the collected statistics or to a manually defined value. This offset is less than the offset of contention for the channel. The STA occupies the channel by sending null or dummy packets until RTA packet arrival.

12. General Scope of Embodiments

[0105] The enhancements described in the presented technology can be readily implemented within various wireless stations, including access points (APs), configured for operation in wireless networks. It should also be appreciated that wireless stations are preferably implemented to include one or more computer processor devices (e.g., CPU, microprocessor, microcontroller, computer enabled ASIC, etc.) and associated memory storing instructions (e.g., RAM, DRAM, NVRAM, FLASH, computer readable media, etc.) whereby programming (instructions) stored in the memory are executed on the processor to perform the steps of the various process methods described herein.

[0106] The computer and memory devices were not depicted in the diagrams for the sake of simplicity of illustration, as one of ordinary skill in the art recognizes the use of computer devices for carrying out steps involved with wireless network communication. The presented technology is non-limiting with regard to memory and computer-readable media, insofar as these are non-transitory, and thus not constituting a transitory electronic signal.

[0107] Embodiments of the present technology may be described herein with reference to flowchart illustrations of methods and systems according to embodiments of the technology, and/or procedures, algorithms, steps, operations, formulae, or other computational depictions, which may also be implemented as computer program products. In this regard, each block or step of a flowchart, and combinations of blocks (and/or steps) in a flowchart, as well as any procedure, algorithm, step, operation, formula, or computational depiction can be implemented by various means, such as hardware, firmware, and/or software including one or more computer program instructions embodied in computer-readable program code. As will be appreciated, any such computer program instructions may be executed by one or more computer processors, including without limitation a general purpose computer or special purpose computer, or other programmable processing apparatus to produce a machine, such that the computer program instructions which execute on the computer processor(s) or other programmable processing apparatus create means for implementing the function(s) specified.

[0108] Accordingly, blocks of the flowcharts, and procedures, algorithms, steps, operations, formulae, or computational depictions described herein support combinations of means for performing the specified function(s), combinations of steps for performing the specified function(s), and computer program instructions, such as embodied in computer-readable program code logic means, for performing the specified function(s). It will also be understood that each block of the flowchart illustrations, as well as any procedures, algorithms, steps, operations, formulae, or computational depictions and combinations thereof described herein, can be implemented by special purpose hardware-based computer systems which perform the specified function(s) or step(s), or combinations of special purpose hardware and computer-readable program code.

[0109] Furthermore, these computer program instructions, such as embodied in computer-readable program code, may also be stored in one or more computer-readable memory or memory devices that can direct a computer processor or other programmable processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory or memory devices produce an article of manufacture including instruction means which implement the function specified in the block(s) of the flowchart(s). The computer program instructions may also be executed by a computer processor or other programmable processing apparatus to cause a series of operational steps to be performed on the computer processor or other programmable processing apparatus to produce a computer-implemented process such that the instructions which execute on the computer processor or other programmable processing apparatus provide steps for implementing the functions specified in the block(s) of the flowchart(s), procedure (s) algorithm(s), step(s), operation(s), formula(e), or computational depiction(s).

[0110] It will further be appreciated that the terms "programming" or "program executable" as used herein refer to one or more instructions that can be executed by one or more computer processors to perform one or more functions as described herein. The instructions can be embodied in software, in firmware, or in a combination of software and firmware. The instructions can be stored local to the device in non-transitory media, or can be stored remotely such as on a server, or all or a portion of the instructions can be stored locally and remotely. Instructions stored remotely can be downloaded (pushed) to the device by user initiation, or automatically based on one or more factors.

[0111] It will further be appreciated that as used herein, that the terms processor, hardware processor, computer processor, central processing unit (CPU), and computer are used synonymously to denote a device capable of executing the instructions and communicating with input/output interfaces and/or peripheral devices, and that the terms processor, hardware processor, computer processor, CPU, and computer are intended to encompass single or multiple devices, single core and multicore devices, and variations thereof.

Claims

1. An apparatus (10) for wireless communication in a network, the apparatus comprising:

(a) a wireless communication circuit (22, 32) configured for wirelessly communicating with at least one other wireless local area network, WLAN, station in its reception area;

(b) a processor (16) coupled to said wireless communication circuit within a station configured for operating on the WLAN; and

(c) a non-transitory memory (18) storing instructions executable by the processor;

(d) wherein said instructions, when executed by the processor, perform one or more steps comprising:

(i) operating said wireless communication circuit as a WLAN station configured to support at least one real-time application, RTA, that is sensitive to communication delays;

(ii) tracking active real-time application sessions and identifying running RTA sessions with respect to communication times, rates and packet sizes;

(iii) determining if pre-packet arrival channel access is to be allowed based on an amount of data to be sent and/or a period of channel access time; and

(iv) attempting, if pre-packet arrival channel access is allowed, to gain access to a communication channel before a packet arrives in a pre-packet arrival channel contention process based on information provided by an application layer of the at least one RTA on what time the packet will arrive to a media access control, MAC, queue in a MAC layer of said WLAN station.

2. The apparatus of claim 1, wherein said instructions, when executed by the processor, perform one or more steps comprising determining said communication times, rates and packet sizes in the form of rate of packet arrival, size of packet to be sent, expected time of packet arrival, and end of a real-time application session.

3. The apparatus of claim 1, wherein said instructions, when executed by the processor, perform one or more steps comprising tracking of statistics to update expected pre-packet channel contention information by said WLAN station each time the communication channel is relinquished.

4. The apparatus of claim 1, wherein said instructions, when executed by the processor, perform one or more steps comprising sending a request from a non-access point, non-AP, station to the AP in its basic service set, BSS, to perform said pre-packet arrival channel contention process in response to exchanging one or more messages or requests between said WLAN station and the AP.

5. The apparatus of claim 4, wherein said instructions, when executed by the processor, perform one or more steps comprising the WLAN station requesting a change of procedure parameters through exchanging parameter update messages with the AP, in response to receiving acceptance of performing said pre-packet arrival channel contention process by the AP.

6. The apparatus of claim 1, wherein said instructions, when executed by the processor, perform one or more steps comprising:

running a counter or timer from a last packet arrival time to an estimated next arrival time for a new packet; and

starting a process of contending for a channel before the counter or timer expires in relation to a time offset from statistics collected on channel contention time or manually defined if the channel was busy at any time after the counter or timer reached a threshold.

7. The apparatus of claim 6, wherein the time offset is bounded by a specific amount not to be exceeded.

8. The apparatus of claim 1, wherein said instructions, when executed by the processor, perform one or more steps comprising:

obtaining access to the channel if it is not busy before the counter or timer expires by a time offset related to the collected statistics or manually defined;

wherein the offset is less than the offset of contention for the channel; and

occupying the channel by said WLAN station by sending non-RTA packets, null, dummy packets until the packet arrives from the real-time application.

9. A method of performing wireless communication in a network, comprising:

(a) operating a wireless communication circuit (22, 32) as a wireless local area network, WLAN, station (10) configured to support at least one real-time application, (RTA, that is sensitive to communication delays when wirelessly communicating with at least one other WLAN station in its reception area;

(b) tracking active RTA sessions and identifying running RTA sessions with respect to communication times, rates and packet sizes;

(c) determining if pre-packet arrival channel access is to be allowed based on an amount of data to be sent and/or a period of channel access time; and

(d) attempting, if pre-packet arrival channel access is allowed, to gain access to a communication channel before a packet arrives in a pre-packet arrival channel contention process based on information provided by an application layer of the at least one RTA on what time the packet will arrive to a media access control, MAC, queue in a MAC layer of said WLAN station.

10. The method of claim 9, further comprising sending a request from a non-access point, non-AP, station to the AP in its basic service set, BSS to perform said pre-packet arrival channel contention process in response to exchanging one or more messages or requests between said WLAN station and the AP.

11. The method of claim 9, further comprising:

running a counter or timer from a last packet arrival time to an estimated next arrival time for a new packet; and

starting a process of contending for a channel before the counter or timer expires in relation to a time offset from statistics collected on channel contention time, or that is manually defined, if the channel was busy at any time after the counter or timer reached a threshold.

12. The method of claim 9, further comprising:

obtaining access to the channel if it is not busy before the counter or timer expires by a time offset related to the collected statistics or manually defined;

wherein the offset is less than the offset of contention for the channel; and

occupying the channel by said WLAN station by sending non-RTA packets, null, dummy packets until the packet arrives from the real-time application.

Ansprüche

1. Vorrichtung (10) zur Drahtloskommunikation in einem Netzwerk, wobei die Vorrichtung umfasst:

(a) eine Drahtloskommunikationsschaltung (22, 32), die dazu ausgelegt ist, drahtlos mit mindestens einer anderen Station eines drahtlosen lokalen Netzwerks, WLAN, in ihrem Empfangsbereich zu kommunizieren;

(b) einen Prozessor (16), der mit der Drahtloskommunikationsschaltung innerhalb einer Station gekoppelt ist, die zum Arbeiten in dem WLAN ausgelegt ist; und

(c) einen nichtflüchtigen Speicher (18), der vom Prozessor ausführbare Anweisungen speichert;

(d) wobei die Anweisungen, wenn sie von dem Prozessor ausgeführt werden, einen oder mehrere Schritte durchzuführen, die umfassen:

(i) Betreiben der Drahtloskommunikationsschaltung als eine WLAN-Station, die dazu ausgelegt ist, mindestens eine Echtzeitanwendung, RTA, zu unterstützen, die empfindlich gegenüber Kommunikationsverzögerungen ist;

(ii) Verfolgen aktiver Echtzeitanwendungssitzungen und Identifizieren laufender RTA-Sitzungen im Hinblick auf Kommunikationszeiten, -raten und Paketgrößen;

(iii) Bestimmen, ob der Kanalzugriff vor der Paketankunft basierend auf einer zu sendenden Datenmenge und/oder einer Periode von Kanalzugriffszeiten erlaubt werden soll; und

(iv) Versuchen, wenn der Kanalzugriff vor der Paketankunft erlaubt ist, Zugriff auf einen Kommunikationskanal zu erlangen, bevor ein Paket in einem Kanalkonfliktprozess vor der Paketankunft eintrifft, basierend auf Informationen, die von einer Anwendungsschicht des mindestens einen RTA über den Zeitpunkt bereitgestellt werden, zu dem das Paket in einer Medienzugriffssteuerungs-, MAC-, Warteschlange in einer MAC-Schicht der WLAN-Station eintreffen wird.

2. Vorrichtung nach Anspruch 1, wobei die Anweisungen, wenn sie vom Prozessor ausgeführt werden, einen oder mehrere Schritte durchführen, die das Bestimmen der Kommunikationszeiten, -raten und -paketgrößen in Form der Paketankunftsrate, der Größe des zu sendenden Pakets, der erwarteten Zeit der Paketankunft und des Endes einer Echtzeitanwendungssitzung umfassen.

3. Vorrichtung nach Anspruch 1, wobei die Anweisungen, wenn sie vom Prozessor ausgeführt werden, einen oder mehrere Schritte durchführen, die das Verfolgen von Statistiken umfassen, um erwartete Kanal-Konfliktinformationen vor Paketen durch die WLAN-Station jedes Mal zu aktualisieren, wenn der Kommunikationskanal aufgegeben wird.

4. Vorrichtung nach Anspruch 1, wobei die Anweisungen, wenn sie vom Prozessor ausgeführt werden, einen oder mehrere Schritte durchführen, die das Senden einer Anforderung von einer Nicht-Zugriffspunkt-Station, Non-AP-Station, an den AP in seinem grundlegenden Dienstesatz, BSS, umfassen, um als Reaktion auf das Austauschen einer oder mehrerer Nachrichten oder Anforderungen zwischen der WLAN-Station und dem AP den Kanalkonfliktprozess vor der Paketankunft durchzuführen.

5. Vorrichtung nach Anspruch 4, wobei die Anweisungen, wenn sie vom Prozessor ausgeführt werden, einen oder mehrere Schritte durchführen, die umfassen, dass die WLAN-Station als Reaktion auf das Empfangen der Annahme des Durchführens des vor der Paketankunft stattfindenden Kanalkonfliktprozesses durch den AP eine Veränderung der Verfahrensparameter durch den Austausch von Nachrichtenaustausch über Parameteraktualisierungen mit dem AP anfordert.

6. Vorrichtung nach Anspruch 1, wobei die Anweisungen, wenn sie von dem Prozessor ausgeführt werden, einen oder mehrere Schritte durchzuführen, die umfassen:

Ausführen eines Zählers oder Timers von einer letzten Paketankunftszeit bis zu einer geschätzten nächsten Ankunftszeit für ein neues Paket; und

Starten eines Konfliktprozesses für einen Kanal, bevor der Zähler oder Timer abläuft, in Bezug auf einen Zeitversatz aus den Statistiken, die zur Kanalkonfliktzeit Kanal gesammelt oder manuell definiert werden, wenn der Kanal zu irgendeinem Zeitpunkt besetzt war, nachdem der Zähler oder Timer einen Schwellenwert erreicht hatte.

7. Vorrichtung nach Anspruch 6, wobei der Zeitversatz auf einen bestimmten Betrag begrenzt ist, der nicht überschritten werden darf.

8. Vorrichtung nach Anspruch 1, wobei die Anweisungen, wenn sie von dem Prozessor ausgeführt werden, einen oder mehrere Schritte durchzuführen, die umfassen:

Erhalten des Zugriffs auf den Kanal, wenn dieser nicht besetzt ist, bevor der Zähler oder Timer um einen Zeitversatz abläuft, der sich auf die gesammelten Statistiken bezieht oder manuell definiert wird;

wobei der Versatz kleiner ist als der Versatz des Konflikts für den Kanal; und

Besetzen des Kanals durch die WLAN-Station durch Senden von Nicht-RTA-Paketen, Null-Paketen, Dummy-Paketen, bis das Paket von der Echtzeitanwendung eintrifft.

9. Verfahren zum Durchführen einer Drahtloskommunikation in einem Netzwerk, umfassend:

(a) Betreiben einer Drahtloskommunikationsschaltung (22, 32) als eine Station (10) des drahtlosen lokalen Netzwerks, WLAN, die dazu ausgelegt ist, mindestens eine Echtzeitanwendung (RTA) zu unterstützen, die empfindlich gegenüber Kommunikationsverzögerungen ist, wenn sie drahtlos mit mindestens einer anderen WLAN-Station in ihrem Empfangsbereich kommuniziert;

(b) Verfolgung aktiver RTA-Sitzungen und Identifizierung laufender RTA-Sitzungen im Hinblick auf Kommunikationszeiten, -raten und Paketgrößen;

( c) Bestimmen, ob der Kanalzugriff vor der Paketankunft basierend auf einer zu sendenden Datenmenge und/oder einer Periode von Kanalzugriffszeiten erlaubt werden soll; und

(d) Versuchen, wenn der Kanalzugriff vor der Paketankunft erlaubt ist, Zugriff auf einen Kommunikationskanal zu erlangen, bevor ein Paket in einem Kanalkonfliktprozess vor der Paketankunft eintrifft, basierend auf Informationen, die von einer Anwendungsschicht des mindestens einen RTA über den Zeitpunkt bereitgestellt werden, zu dem das Paket in einer Medienzugriffssteuerungs-, MAC-, Warteschlange in einer MAC-Schicht der WLAN-Station eintreffen wird.

10. Verfahren nach Anspruch 9, das ferner das Senden einer Anforderung von einer Nicht-Zugriffspunkt-Station, Non-AP-Station, an den AP in seinem grundlegenden Dienstsatz, BSS, umfasst, um als Reaktion auf das Austauschen einer oder mehrerer Nachrichten oder Anforderungen zwischen der WLAN-Station und dem AP den Kanalkonfliktprozess vor Paketankunft durchzuführen.

11. Verfahren nach Anspruch 9, ferner umfassend:

Ausführen eines Zählers oder Timers von einer letzten Paketankunftszeit bis zu einer geschätzten nächsten Ankunftszeit für ein neues Paket; und

Starten eines Konfliktprozesses für einen Kanal, bevor der Zähler oder Timer abläuft, in Bezug auf einen Zeitversatz aus den Statistiken, die zur Kanalkonfliktzeit gesammelt werden, oder der manuell definiert wird, wenn der Kanal zu irgendeinem Zeitpunkt besetzt war, nachdem der Zähler oder Timer einen Schwellenwert erreicht hatte.

12. Verfahren nach Anspruch 9, ferner umfassend:

Erhalten des Zugriffs auf den Kanal, wenn dieser nicht besetzt ist, bevor der Zähler oder Timer um einen Zeitversatz abläuft, der sich auf die gesammelten Statistiken bezieht oder manuell definiert wird;

wobei der Versatz kleiner ist als der Versatz des Kanalkonflikts; und Besetzen des Kanals durch die WLAN-Station durch Senden von Nicht-RTA-Paketen, Null-, Dummy-Paketen, bis das Paket von der Echtzeitanwendung ankommt.

Revendications

1. Appareil (10) de communication sans fil dans un réseau, l'appareil comportant :

(a) un circuit (22, 32) de communication sans fil configuré pour communiquer sans fil avec au moins une autre station de réseau local sans fil, WLAN, dans sa zone de réception ;

(b) un processeur (16) couplé audit circuit de communication sans fil au sein d'une station configurée pour fonctionner sur le WLAN ; et

(c) une mémoire non transitoire (18) conservant des instructions exécutables par le processeur ;

(d) lesdites instructions, lorsqu'elles sont exécutées par le processeur, réalisant une ou plusieurs étapes comportant celles consistant à :

(i) faire fonctionner ledit circuit de communication sans fil comme une station de WLAN configurée pour prendre en charge au moins une application en temps réel, RTA, qui est sensible aux retards de communication ;

(ii) suivre des sessions actives d'application en temps réel et identifier des sessions de RTA en cours par rapport à des temps de communication, à des débits et à des tailles de paquets ;

(iii) déterminer si un accès à des canaux avant l'arrivée de paquets doit être autorisé d'après une quantité de données à émettre et/ou une période d'accès aux canaux ; et

(iv) tenter, si l'accès aux canaux avant l'arrivée de paquets est autorisé, d'accéder à un canal de communication avant qu'un paquet arrive dans un processus de contention de canaux avant l'arrivée de paquets d'après des informations fournies par une couche d'application de la ou des RTA sur l'instant auquel le paquet arrivera à une file d'attente de commande d'accès au support, MAC, dans une couche MAC de ladite station de WLAN.

2. Appareil selon la revendication 1, lesdites instructions, lorsqu'elles sont exécutées par le processeur, réalisant une ou plusieurs étapes comportant la détermination desdits temps de communication, desdits débits et desdites tailles de paquets sous la forme d'un débit d'arrivée de paquets, d'une taille de paquet à émettre, d'un instant prévu d'arrivée de paquet, et de la fin d'une session d'application en temps réel.

3. Appareil selon la revendication 1, lesdites instructions, lorsqu'elles sont exécutées par le processeur, réalisant une ou plusieurs étapes comportant le suivi de statistiques pour l'actualisation d'informations prévisionnelles de contention de canaux avant l'arrivée de paquets par ladite station de WLAN chaque fois que le canal de communication est cédé.

4. Appareil selon la revendication 1, lesdites instructions, lorsqu'elles sont exécutées par le processeur, réalisant une ou plusieurs étapes comportant l'envoi d'une demande d'une station hors point d'accès, hors AP, à l'AP dans son ensemble de services de base, BSS, pour réaliser ledit processus de contention de canaux avant l'arrivée de paquets en réponse à l'échange d'un ou de plusieurs messages ou demandes entre ladite station de WLAN et l'AP.

5. Appareil selon la revendication 4, lesdites instructions, lorsqu'elles sont exécutées par le processeur, réalisant une ou plusieurs étapes comportant la demande, par la station de WLAN, d'un changement de paramètres de procédure par l'intermédiaire d'un échange de messages d'actualisation de paramètres avec l'AP, en réponse à la réception d'une acceptation de la réalisation dudit processus de contention de canaux avant l'arrivée de paquets par l'AP.

6. Appareil selon la revendication 1, lesdites instructions, lorsqu'elles sont exécutées par le processeur, réalisant une ou plusieurs étapes comportant celles consistant à :

faire fonctionner un compteur ou un temporisateur d'un instant d'arrivée du dernier paquet à un instant d'arrivée suivant estimé pour un nouveau paquet ; et

commencer un processus de contention pour un canal avant que le compteur ou le temporisateur expire en relation avec un décalage temporel issu de statistiques collectées sur le temps de contention pour le canal ou défini manuellement si le canal était occupé à un instant quelconque après que le compteur ou le temporisateur a atteint un seuil.

7. Appareil selon la revendication 6, le décalage temporel étant borné par une quantité spécifique à ne pas dépasser.

8. Appareil selon la revendication 1, lesdites instructions, lorsqu'elles sont exécutées par le processeur, réalisant une ou plusieurs étapes comportant :

l'obtention de l'accès au canal s'il n'est pas occupé avant que le compteur ou le temporisateur expire d'un décalage temporel lié aux statistiques collectées ou défini manuellement ;

le décalage étant inférieur au décalage de contention pour le canal ; et

l'occupation du canal par ladite station de WLAN en émettant des paquets non-RTA, des paquets nuls, des paquets factices jusqu'à ce que le paquet arrive en provenance de l'application en temps réel.

9. Procédé de réalisation d'une communication sans fil dans un réseau, comportant les étapes consistant à :

(a) faire fonctionner un circuit (22, 32) de communication sans fil comme une station de réseau local sans fil, WLAN, (10) configurée pour prendre en charge au moins une application en temps réel, RTA, qui est sensible aux retards de communication lors d'une communication sans fil avec au moins une autre station de WLAN dans sa zone de réception ;

(b) suivre des sessions actives de RTA et identifier des sessions de RTA en cours par rapport à des temps de communication, à des débits et à des tailles de paquets ;

(c) déterminer si un accès à des canaux avant l'arrivée de paquets doit être autorisé d'après une quantité de données à émettre et/ou une période d'accès aux canaux ; et

(d) tenter, si l'accès aux canaux avant l'arrivée de paquets est autorisé, d'accéder à un canal de communication avant qu'un paquet arrive dans un processus de contention de canaux avant l'arrivée de paquets d'après des informations fournies par une couche d'application de la ou des RTA sur l'instant auquel le paquet arrivera à une file d'attente de commande d'accès au support, MAC, dans une couche MAC de ladite station de WLAN.

10. Procédé selon la revendication 9, comportant en outre l'envoi d'une demande d'une station hors point d'accès, hors AP, à l'AP dans son ensemble de services de base, BSS pour réaliser ledit processus de contention de canaux avant l'arrivée de paquets en réponse à l'échange d'un ou de plusieurs messages ou demandes entre ladite station de WLAN et l'AP.

11. Procédé selon la revendication 9, comportant en outre les étapes consistant à :

faire fonctionner un compteur ou un temporisateur d'un instant d'arrivée du dernier paquet à un instant d'arrivée suivant estimé pour un nouveau paquet ; et

commencer un processus de contention pour un canal avant que le compteur ou le temporisateur expire en relation avec un décalage temporel issu de statistiques collectées sur le temps de contention pour le canal, ou qui est défini manuellement, si le canal était occupé à un instant quelconque après que le compteur ou le temporisateur a atteint un seuil.

12. Procédé selon la revendication 9, comportant en outre :

l'obtention de l'accès au canal s'il n'est pas occupé avant que le compteur ou le temporisateur expire d'un décalage temporel lié aux statistiques collectées ou défini manuellement ;

le décalage étant inférieur au décalage de contention pour le canal ; et

l'occupation du canal par ladite station de WLAN en émettant des paquets non-RTA, des paquets nuls, des paquets factices jusqu'à ce que le paquet arrive en provenance de l'application en temps réel.

Drawing